1. Field of the Invention
The present invention relates to a crown forming apparatus for forming a crown on the floating surface of a floating type magnetic head.
2. Description of the Related Art
Floating type magnetic heads record and reproduce information to and from magnetic recording mediums while floating therefrom.
The floating type magnetic head is operated by a so-called CSS system in such a manner that it is floated from the magnetic recording medium by the movement thereof and placed on the magnetic recording medium again when it stops.
Since the surfaces of the floating type magnetic head and the magnetic recording medium, which confront each other, have high flatness, they are liable to be adsorbed by each other. Thus, it is possible that a drawback is caused to the floating type magnetic head and the magnetic recording medium.
To cope with this problem, the absorption between the floating type magnetic head and the magnetic recording medium is prevented by forming the floating surface of the floating type magnetic head to a convex surface so as to reduce the area where the floating surface is in contact with the magnetic recording medium.
The convex surface formed on the floating surface is referred to as a crown. Various methods are conventionally employed to form the crown.
Conventional methods of forming a crown on a floating type magnetic head will be described with reference to drawings.
FIGS. 15A-15E show a first example of the conventional methods of forming a crown on a floating type magnetic head.
In FIGS. 15A-15E, an approximately rectangular-prism-shaped bar 61 having floating type magnetic head elements disposed thereto in a row and a groove jig 62 are prepared.
The bar 61 has the plurality of magnetic head elements formed on a surface (left side surface) 61a thereof. The bar 61 is made in such a manner that a wafer having a multiplicity of magnetic head elements formed thereto is cut to have an approximately rectangular-prism-shape and other surface (bottom surface) 61c is polished and the gaps between the magnetic head elements and coils are adjusted. Further, the groove jig 62 has a groove 62a formed on a surface (upper surface) thereof.
Next, a melted wax 63 is coated to the groove 62a and the bar 61 is placed on the groove jig 62 with the other surface 61c facing downward so that the other surface 61c comes into contact with the wax 63.
Then, the wax 63 is cooled and solidified so that it is contracted, whereby the bar 61 is deformed to an arc-shape. The bar 61 is fixed to the groove jig 62 by the wax 63. At the time, the other surface 61c of the curved bar is made to a convex surface.
Subsequently, the surface 61b of the bar 61, which is curved in confrontation with the other surface 61c is polished and flatly cut, thereby obtaining the floating type magnetic head.
A floating type magnetic head is obtained by removing the bar 61 from the groove jig 62 and cutting it in the longitudinal direction thereof at equal intervals.
The floating type magnetic head has a crown which is made to the convex surface by the deformation of the bar 61.
FIGS. 16A-16C show a second example of the conventional methods of forming a crown on a floating type magnetic head.
In FIGS. 16A-16C, first, an approximately rectangular-prism-shaped magnetic head slider 71 is prepared. The magnetic head slider 71 has magnetic head elements (not shown) previously disposed thereon. Further, the magnetic head slider 71 has a pair of rails 72a and 72a formed on the floating surface 72 thereof.
Next, a laser beam 74 is irradiated between the rails 72a and 72a of the magnetic head slider 71 so as to form a plurality of cracks 73 . . . along the short direction of the magnetic head slider 71.
Subsequently, the magnetic head slider 71 is deformed to an arc shape along the longitudinal direction thereof, thereby making the floating surface 72 of the magnetic head slider 71 to a convex surface. Since the cracks 73 . . . are formed on the floating surface 72, the magnetic head slider 71 can be easily deformed. With this process, a crown is formed on the floating surface 72 of the magnetic head slider 71.
FIGS. 17A-17E show a third example of the conventional methods of forming a crown on a floating type magnetic head.
In FIG. 17A-17E, first, an approximately rectangular-prism-shaped magnetic head slider 81 is prepared. Further, a lapping surface plate 85 having a concave processing surface 85a is prepared.
Magnetic head elements (not shown) are previously formed on the magnetic head slider 81. Further, a pair of rails 82a and 82a are formed on the floating surface 82 of the magnetic head slider 81.
Next, the magnetic head slider 81 is fixed on the flat surface 84a of a jig 84 through an elastic sheet 83 with the floating surface 82 facing upward.
Then, the jig 84, on which the magnetic head slider 81 is fixed, is placed on the fixing plate 85 in such a manner that the floating surface 82 of the magnetic head slider 81 is abutted against the processing surface 85a of the fixing plate 85.
Subsequently, a polishing agent is sprayed on the processing surface 85a and the processing surface 85a is pressed against the floating surface 82 by imposing a load on the magnetic head slider 81 by the jig 84. Further, the jig 84 is rotated while rotating the lap fixing plate 85 so that lapping is carried out by causing the floating surface 82 of the magnetic head slider 81 and the processing surface 85a to slide each other.
At the time, since the shape of the processing surface 85a is transferred onto the floating surface 82, the floating surface 82 is formed to a convex surface having a radius of curvature similar to that of the processing surface 85a.
The thus obtained magnetic head slider 81 has a crown 87 formed thereon which has a convex surface along the longitudinal direction and the short direction of the magnetic head slider 81.
FIGS. 19A-19F show a fourth example of the conventional methods of forming a crown on a floating type magnetic head.
In FIGS. 19A-19F, first, an approximately rectangular-prism-shaped bar 127 is prepared. The bar 127 is made in such a manner that after a multiplicity of head elements are formed on a surface of a wafer composed of a material of the slider of a floating type magnetic head using a thin film forming technology or the like, a portion of the wafer is cut to a rectangular-prism-shape. A plurality of magnetic head elements 128 . . . are disposed on a side wall of the bar 127 in a row.
Next, a spring type concave/convex jig 129 is mounted on the bar 127.
The spring type concave/convex jig 129 is composed of a spring sheet 130 and a concave/convex sheet 131 jointed to both the ends of the spring sheet, and grooves 132 are formed to the concave/convex sheet 131 at predetermined intervals. The spring type concave/convex jig 129 can be elastically deformed along the longitudinal direction thereof.
The bar 127 is mounted on the spring type concave/convex jig 129 such that the grooves 132 of the spring type concave/convex jig 129 are located between the respective magnetic head elements 128 . . .
Next, the bar 127 is cut at equal intervals along the short direction thereof and made to chips 138 . . . The 127 is cut at the positions of the grooves 132 of the spring type concave/convex jig 129.
Next, the spring type concave/convex jig 129 is mounted on a columnar jig 133. An elastic member 134 is interposed between the spring type concave/convex jig 129 and the columnar jig 133.
Further, one surfaces 136 . . . of the respective chips 138 . . . are pressed against a concave processing surface 135 and the one surfaces 136 . . . are subjected to lapping by moving the columnar jig 133 relative to the processing surface 135.
Since the processing surface 135 is formed to the concave surface, the spring type concave/convex jig 129 and the elastic member 134 are elastically deformed so that the one surfaces 136 . . . of all the chips 138 . . . come into contact with the processing surface 135.
The shape of the processing surface 135 is transferred onto the one surfaces 136 . . . of the chips 138 . . . by the lapping.
Finally, a floating type magnetic head 137 is obtained by removing the respective chips 138 . . . from the spring type concave/convex jig 129. With this processing, a convex crown is formed on the one surface 136 (floating surface) of the floating type magnetic head 137 in the longitudinal direction thereof and at the same time a convex cross crown is formed in the short direction thereof.
However, the first example of the conventional methods of forming a crown on a floating type magnetic head has a problem in that the shapes of crowns are liable to be varied because the formation of the crowns depends on the contraction of the wax 63 and the groove 62a of the groove jig 62.
The second example of the conventional methods of forming a crown on a floating type magnetic head has a problem in that a process is complicated and productivity is low because the cracks 73 must be formed by irradiating the laser beam 74 a plurality of times.
In addition to the above problem, the second example has a problem that the respective curvatures of the crown and the cross crown cannot be independently adjusted.
The third example of the conventional methods of forming a crown on a floating type magnetic head has a problem in that productively is low because the magnetic head sliders 81 are handled one by one. In addition, the third example has another problem in that the shape of the crown is made to the convex surface which is convex in the longitudinal direction and the short direction of the magnetic head slider 81 and thus a crown which is convex only in the longitudinal direction of the magnetic head slider 81 cannot be formed.
In contrast, the fourth example of the conventional methods of forming a crown on a floating type magnetic head has a problem in that the shape of the processing surface 135 must be changed to change the shapes of the crown and the cross crown because the processing surface 135 is transferred onto the crown and the cross crown.
An object of the present invention, which was made to solve the above problems, is to provide a crown forming method having high productivity and capable of forming a crown which is convex only in the longitudinal direction of a slider with a less amount of variation of the shape of the crown.
An object of the present invention is to provide a crown forming apparatus having high productivity and capable of forming a crown which is convex only in the longitudinal direction of a slider with a less amount of variation of the shape of the crown.
An object of the present invention is to provide a method of forming a crown on a floating type magnetic head having high productivity and capable of simultaneously forming a crown and a cross crown with a less amount of variation of the shapes of the crown and the cross crown and easily changing the shapes of the crown and the cross crown.
An object of the present invention is to provide a crown forming apparatus having high productivity and capable of simultaneously forming a crown and a cross crown with a less amount of variation of the shapes of the crown and the cross crown and easily changing the shapes of the crown and the cross crown.